Index: /applications/editors/josm/plugins/multipoly/src/multipoly/MultipolyAction.java
===================================================================
--- /applications/editors/josm/plugins/multipoly/src/multipoly/MultipolyAction.java	(revision 19137)
+++ /applications/editors/josm/plugins/multipoly/src/multipoly/MultipolyAction.java	(revision 19138)
@@ -33,5 +33,5 @@
  * New relation with type=multipolygon is created
  *
- * If one or more of ways is already in relation with type=multipolygon or the way os not closed,
+ * If one or more of ways is already in relation with type=multipolygon or the way is not closed,
  * then error is reported and no relation is created
  *
@@ -49,5 +49,4 @@
   Shortcut.registerShortcut("tools:multipoly", tr("Tool: {0}", tr("Create multipolygon")),
   KeyEvent.VK_M, Shortcut.GROUP_EDIT, Shortcut.SHIFT_DEFAULT), true);
-  setEnabled(true);
  }
 
@@ -144,3 +143,17 @@
  }
 
+ /** Enable this action only if something is selected */
+ @Override protected void updateEnabledState() {
+  if (getCurrentDataSet()==null) {
+   setEnabled(false);
+  } else {
+   updateEnabledState(getCurrentDataSet().getSelected());
+  }
+ }
+
+ /** Enable this action only if something is selected */
+ @Override protected void updateEnabledState(Collection<? extends OsmPrimitive> selection) {
+  setEnabled(selection != null && !selection.isEmpty());
+ }
+
 }
Index: /applications/editors/josm/plugins/multipoly/src/multipoly/MultipolyPlugin.java
===================================================================
--- /applications/editors/josm/plugins/multipoly/src/multipoly/MultipolyPlugin.java	(revision 19137)
+++ /applications/editors/josm/plugins/multipoly/src/multipoly/MultipolyPlugin.java	(revision 19138)
@@ -35,5 +35,5 @@
       toolsMenu.add(new JMenuItem(new MultipolyAction()));
     }
-    
+
   }